A lithography technology is a method for forming a micro pattern on a targeted substrate. A nano/micro-scale lithography technology is a core technology which dominates the development and the success or failure of semiconductor and display industries.
Limiting factor which is radically encountered upon micro patterning is a wavelength of light used in the lithography. A mercury UV lamp has been used in the case of a circuit having a line width of 0.8 μm or more but a new light source is required to pattern a line width lower than that, and a 0.13 μm process may be implemented by a kripton fluoride (KrF) excimer laser (wavelength=248 nm), and as a sub 90 nm process is required, an argon fluoride (ArF) excimer laser (wavelength=193 nm) has been used.
To use a shorter wavelength than the ArF excimer laser, a fluorine excimer laser (wavelength=157 nm) needs to be used. However, the fluorine excimer laser may cause several problems such as a reduction in numerical aperture of a lens system, and in the case of using extreme ultraviolet rays, a very expensive photo mask is required and therefore the fluorine excimer laser is hardly commercialized and in the case of using electron beam, an operation speed is very slow and equipment is expensive, which hinders practical application of the fluorine excimer laser.
Further, as disclosed in Korean Patent Laid-Open Publication No. 2010-0076680, when the micro pattern to be manufactured is sophisticated like a ring (circular ring) form, an expensive phase shift mask (PSM) in which a complicated surface ruggedness or a micro structure is formed has been used. However, the above-mentioned method inevitably involves the design and manufacturing the expensive mask and the development of a separate optical system for lithography, and therefore huge costs and research and development have to be preceded.
As described above, a new technology capable of patterning the sophisticated shape like the micro ring pattern at low cost and by the exiting lithography process and equipment is required.